Balbiani on the Reproduction of Infusoria. 463 



death at the close of his career ; for as disease was busy chang- 

 ing his mortal state, he studied the phenomena of a dissolution, 

 of which his religious nature had no fear. 



His greatest works remain behind in the moral and intellec- 

 tual elevation of his pupils, his parishioners and his friends ; 'but 

 his writings were numerous, not the least important being the 

 elementary, such as the " Practical Lessons in Botany," com- 

 piled for the South Kensington Museum, and his admirable 

 ' l Dictionary of Botanical Terms,"* which is an invaluable aid to 

 the regular student, and a work of constant usefulness in 

 family circles where scientific tastes prevail. In this excel- 

 lent little volume each word is clearly explained, and its deriva- 

 tion given, while numerous woodcuts convey at once to the eye 

 the information which words alone might fail to give. 



BALBIANI ON THE REPRODUCTION OF 

 INFUSORIA.t 



Oue present object in dealing with M. Balbianr's researches is 

 expository, not critical, so for the sake of brevity we omit 

 historical details and pass at once to his declaration that 

 ' ' Infusoria, like other animals, propagate at certain epochs 

 with the aid of elements characterizing sexual generation .". 

 These elements originate in the interior of organs known as 

 the nucleus and nucleolus. The nucleus is the producer of 

 germs or ovules, the nucleolus develops fecundating corpuscules, 

 or zoosperms. The first may be considered as the ovary, the 

 second as the testicle of infusoria. These two organs consti- 

 tute all the sexual apparatus of these animals. In some 

 cases an excretory chanuel seems added to the ovary, and 

 perhaps also to the testicle, and appears to open directly out- 

 side. The reproductive organs are always distinct, though united 

 in one individual ; but the hermaphrodism which results from 

 this arrangement is not complete, as the concurrence of two 

 individuals is always needful for the process of fecundation, 

 which takes place inside the creatures, and requires the trans- 

 port of the male elements of one to the female organs of the 

 other. 



The situation of these organs varies considerably, not only 

 in different groups, but also in different species of the same 



* A Dictionary of Botanical Terms, by the Rev. J. S. Henslow, M.A., Pro- 

 fessor of Botany in the University of Cambridge, new edition, illustrated by 

 nearly Two Hundred Cuts. Groombridge and Sons. 



t Recherches sur les Phenomenes Sexuels des Infusoires, par le Docteur G-. 

 Balbiani. Yictor Masson, Paris, 1S61. 



